How New Statin Rules Will Affect Drug Stocks

AstraZeneca gets clean bill of health, but the prognosis is not so hot for Merck and two others.

For years, doctors have followed a simple approach to reduce patients' risk of heart attack and stroke. The strategy has been to use statins and other drugs to reduce LDL, or bad cholesterol, to specific target levels.

Then earlier this month, the American Heart Association and the American College of Cardiology scrapped...